Chevy Impala SS Forum banner
Cancel
Create thread New Garage Forums

intake Manifold/Gasket replacement ??'s

Jump to Latest
16K views 45 replies 9 participants last post by  4DoorSS  
#1 ·
Just discovered what I think is JUST a Gasket leak at the Intake manifold. Found a pretty bad leak that only was leaking when the car was running the Water Pump. After removing some items to get a good look, I found coolant pooling up on the top of the Driver Side Intake manifold.

While there is really no hoses or anything in this area, this leads me to believe the Intake Gasket is leaking and letting coolant come out between the Intake and Head. Fortunately there is no coolant in the oil, so it looks like it was just pushing the coolant out of the Block and not into it. Should consider myself lucky I guess.

I'm going through threads now to see what info may already be put out there in the Forum. Any pointers, thoughts, steps or things to consider before pulling the manifold and during replacement would be appreciated. I already have the Fuel rail and Throttle Body and EGR Metal Hose removed and about ready to remove the intake bolts and Manifold. I sure dont want to get things back together only to find out I missed something. Thx....Happy New Year....not so Happy for me.
 
Save
Reply Quote Like Like
#2 · (Edited)
IIRC there is no water passage from head to intake manifold on the LT1 engine.

It is possible that you have a bad gasket or hose on the throttle body which is leaking coolant onto the intake left front corner. That water comes from the rear steam tube into the throttle body then returns to the reservoir. Make sure you check that area real good.
 
#4 ·
Damn....you guys are bringing up good points. Thinking with my SBC brain again and assumed there was coolant going through the intake. No clue where this could have been coming from then. It's dry at the back of the motor so dont think its the banjo bolts back there for the crossover tube.

Now I dont know what to do or what it could be. I'll take a closer look and see what I can find and report back. Sounds like I may want to hold off pulling the intake at this point. Just warming up a bit before I head back to the ice box garage. I'll report back with what I find....hope i find something. Any other ideas why the coolant would be dripping out of what appeared to be the intake manifold on the Driver Side? The WP is dry and the hoses all looked good and tight. The WP also has a drain hose so it was not coming from the WP itself.

BTW - I have done the coolant bypass on the TB so the hose does not go over to the TB but instead connects to the Crossover Tube on the pass side that runs to the back banjo bolts. I'm really at a loss on this after hearing your feedback on the whole no coolant in an intake thing. DAMN!!
 
Save
Reply Quote Like Like
B
#5 ·
finding coolant on DS of intake???

"maybe" there is a pin hole leak top DS of radiator or that hose pissing on that part of the motor

I misread and though you said PS which is why I noted the steam pipe/hose connection on that side

Is stat housing show any signs of leak??
 
#7 · (Edited)
Not that they are probably needed, but attached are 2 pics of the motor. The first is as things look now and the intake has not been removed yet. The 2nd pic I'm using the Orange Tip of the Pry Bar to show the area where I saw coolant seeping out. It was pooled up in that area as well as the area below the PCV Valve. The back end of the Car is probably about a foot higher as I have the rear jacked up (for exhaust replace) and the front tires on car ramps.

The more I look at this, I just cant see where else it would be leaking from. Its an area that is completely above all the other normal leak areas like the WP, Freeze Plugs and Knock sensor. I really cant understand this leak if its not the intake.




Sorry, if I got my sides mixed up, but it is leaking at the Driver side. The hoses all look good and weren't wet. It really appeared to be coming from around the seam of the Intake to Head area. Besides, I would think the coolant system would need to be up to pressure for this to spray like that anyway. And it started to leak right away when the car was cold and just idling. So it seems to happen as soon as coolant is flowing.

gbhs72 said:
4DOOR, Would pressurizing the system help? I don't know the LT motors that well. I think AZ has a loaner you could use.

Mark: Snowman-33
Click to expand...
Didn't even think of getting the system pressurized and that is a Great idea. I just dont know if there is a pressurizer in the Loan a Tool that has fittings for the Reservoir Tank but will look into this for sure.

Just did a very Stupid thing....with all stuff disconnected, I tried to just crank the engine to get the WP to turn. Completely forgot I had the fuel rail removed, forgot to remove the FP fuse and blew Fuel all over the place. :crying: It's been a Great Year so far....1 day in. :smile2:

Not too bad but its hard to work down there now until the fumes are gone. Gives me a headache. I will look into the pressurizer for the coolant system and maybe someone has recommendations on this or where to get one for the LT1 Engine. Hoping I can just do loan a tool. This thing has really got me stumped at the moment.

EDIT - Just talking to the SIL and he has a Pressure Setup that will work on the LT1. So at least I can pressurize it first before tearing into this further. We're down to 1 car now so I may need to take some time off end of the week to finish things up. I'll probably move onto the Opti rebuild first and then track down this leak once i get the pressure tester. Fun times
 

Attachments

Save
Reply Quote Like Like
B
#8 ·
There is no water flow through the intake so it can't come "from" it. If you blew a head gasket and somehow the coolant between head & block "migrated" up and through a intake bolt...just don't see how that can happen

If I understand right you see coolant with just motor running...put the injectors, etc, back on and watch wtf it may be coming from

maybe the T Stat gasket letting coolant mist/piss in that direction to land on intake...but you should be able to see that happening

if you use a pressure tester...don't go uber nuts on pressure. 15 psi max

must have been quite a gas bath with open fuel lines :-(

is it possible the injector closest to where you see what appears to be coolant gathering the O ring is bad and leaking out fuel....although that would not be green in color

weird one
 
#12 ·
It was just sheer forgetfulness on my part as I tried to crank the motor. Wasn't too bad but it went primarily on the intake and dripped on the floor. So wasn't too bad but just dealing with fumes now. Really smells bad down (garage under house) there and had to open the garage door to let it air out and it's about 10* outside.

Nothing at the Tstat or hoses that were leaking. Head gasket is my worst fear, but could it leak like this and no go into the engine? Pulling the plugs may also reveal some things and plan on doing that when I rebuild the Opti.
 
Save
Reply Quote Like Like
#10 ·
Thanks but the Tstat and gasket are not that old. There was no leaking at the top of the WP.

Another thought based on something I read in the Haynes manual. They mention to put non hardening sealant on the intake manifold bolts. But think this also covers the early model cars before the LT1.

But question is....do any of the intake bolts go into water jackets on the heads for an LT1 setup?
 
Save
Reply Quote Like Like
#16 ·
Ok, so if I'm understanding this correctly, then it is possible that's where the coolant was coming from. The more I think about this and what I saw on the intake and how the car was tilted, it must have been coming from the Intake bolts under the PCV Valve area. It would pool up there, then flow down to the area below the TB linkage on top of the intake and then drip over the top front edge of the manifold/Block area.

The car is tilted forward about 15* right now. Coolant was pooling up under the PCV valve and also under the TB Linkage. Nothing at the back side of the intake toward the EGR valve. So with the car at this angle, coolant must have come up the intake bolts to get on top of the intake manifold like that? Does this sound like a logical explanation?

Just cant believe on a Motor with no coolant going thru the intake, that they would have the intake bolts go into Water jackets on the heads. I guess GM has done crazier things. I may just remove those bolts without pulling the intake and use some sealer on them.
 
Save
Reply Quote Like Like
B
#13 ·
Got Gupcake Bearings had his Combination Motorsports ported heads go because they took a little to much port work and a hair crack developed causing coolant to enter motor. IDK how the coolant would migrate "up" from combustion chamber, through a bolt hole and appear on intake though

I thought you mentioned you can see coolant dripping with engine running...gotta be able to find that kind of leak and pulling the intake would not be involved for that

"maybe" the bolt itself just needs to be pulled and thread sealer applied if it is leaking from that intake bolt. Would only take a few min to do that one bolt
 
#14 ·
Just did a very Stupid thing....with all stuff disconnected, I tried to just crank the engine to get the WP to turn. Completely forgot I had the fuel rail removed, forgot to remove the FP fuse and blew Fuel all over the place. :crying: It's been a Great Year so far....1 day in. :smile2:

Sure glad you didn't have that propane heater causing a fire there.

EDIT - Just talking to the SIL and he has a Pressure Setup that will work on the LT1. So at least I can pressurize it first before tearing into this further. We're down to 1 car now so I may need to take some time off end of the week to finish things up. I'll probably move onto the Opti rebuild first and then track down this leak once i get the pressure tester. Fun times[/QUOTE]

I have nothing but time. Will work for dippy eggs, scrapple & shoo fly pie. :laugh:

Mark: Snowman-33
 
Save
Reply Quote Like Like
#15 ·
If there is water leaking between the block and heads and the secondary fan turns on it WILL force the water towards the firewall and probably get up onto the intake manifold. A pressure tester hooked up MIGHT reveal that but I would suggest having the engine running when looking for it as the compression from the cylinder might be what's forcing water out and wouldn't be detected if engine isn't running.
 
#21 · (Edited)
Here's some pics 4 Doors if it helps. I replaced my intake gasket last year.Definitelty use the thread sealer on the bolts to prevent oil from wicking up the threads.There are no intake bolt holes that go into coolant passages. Be sure to get all gasket surfaces absolutely clean/degreased. I ran a 1/4" x 1/4" bead of the gasket maker in the pic on the china walls,and continued it up on the heads a 1/4" as well.
Good luck hope you find your coolant leak. FWIW,prior to me doing the intake,my t-stat housing and gasket were leaking a pinch, and the fan did push coolant up onto area below throttle body and linkage.

Jim
 
#26 · (Edited)
Appreciate you taking the time to post up the info and pics. And thats where I was/am confused cause it sure did not look like the manifold bolts went into any of the coolant jackets. Will be picking up the FelPro intake kit on my way home tonight.

I appreciate all the thoughts on the T-Stat and Housing from everyone here but trust me....that is not the issue. It was perfectly dry and the fans were not even running yet and the car was just idling in the garage and it started to leak right away at the intake.

BALLSS said:
I know Op said he has replaced stat & gasket not long ago....still worth checking though

Is the black T stat housing aftermarket?
Click to expand...
The stat is so new that I'm not even going to bother replacing the T-Stat. I will most likely Flush the HC again though while the system is down.

The Black Housing is just a Stock GM housing that I had Powder Coated Black along with the front WP cover. Dont see it much but at least I know it's there. :wink2: Just like the Shaved IAC Housing (cut off the Coolant section) which is also Powder Coated but dont see that at all.
 
Save
Reply Quote Like Like
#22 ·
4Door,
As I said before, I"m no LT guru but I too don't see how water could migrate to the area you're telling us about. I might see it if you have a blown head gasket. If that is the case then I would check the compression. That and do the pressurizing since your SIL has the setup for that. Nothing ventured nothing gained.

Mark: Snowman-33
 
Save
Reply Quote Like Like
#24 · (Edited)
remove the TB coolant lines bypass them see if it still leaks ...

steam pipe or the TB ...

if you do have to take it off when installing I use a couple of bolts[no heads] or rods that fit into the manifold hold down threads. this will prevent any sliding messing up the liquid sealer on the front, back . let it setup for 30- 45 min then put it on... the hard part is setting the intake in place perfect drop straight down ... be very careful on the injector wiring and connector / cable harness .
might be good to replace the PCV intake grommet if weeping/loose..

I have a 5.3L in my 2000 silverado that has with the cold extremely cold temps 5F creating high fuel trims . these engines have defective upper intake gaskets . what happened is these gaskets GM , are not compatible with alcohol fuels so they breakdown and crack. It appears I have very small leaks and with the extremely cold temps the air is more dense creating the PCM to see that the fuel trims peg out . then the lean codes . very common gasket failure,.. felpro is the recommended gasket kit. a lot more complicated but no coolant on this upper intake .
 
B
#25 ·
j cat said:
remove the TB coolant lines bypass them see if it still leaks ...

steam pipe or the TB ...

.
Click to expand...
4DoorSS said:
BTW - I have done the coolant bypass on the TB so the hose does not go over to the TB but instead connects to the Crossover Tube on the pass side that runs to the back banjo bolts.
Click to expand...
...and the reported coolant pooling is on DS, not PS of intake
 
B
#27 ·
Well Bob, like yourself we to can't see wtf there is coolant there. The front & rear intake bolts go into head "close" to water jacket which somehow may have developed a small crack letting coolant come up a bolt buy very unlikely

you have the drain hose mod for WP weep hole so coolant contamination into opti should not exist from that source. Yeah the vent hose runs right where your coolant pooling is but for the vent harness to drink up that much coolant and leak it there is also as far fetched

Maybe pulling the intake will reveal something but my $.02 is quite skeptical on that

There are two FelPro gasket sets. One is called "printo" which has the blue sealant around the ports. IMHO a better sealing one but the regular should be fine, especially on a stock head/intake motor

A Few intake R&R tips I found helpful

vacuum all around intake before removing it to clean up any debris that could fall into motor

Use a piece of cardboard and mark one end front. punch holes on each side and put intake bolts in order so you put the right ones back where they belong. Some have studs on them.

If intake does not just lift up when all bolts are removed (and if it does it was not sealed well) use a pry bar/big long screw driver on the front PS lip under intake manifold to pry it off. Can take some effort

cover lifter valley with rags and use rags or paper towels in head intake ports to keep the crap you will be scraping off from getting in motor

scotch brite pads help clean up the RTV

wipe the entire head & china wall areas with acetone...a few times before install of gaskets & RTV

Use Pernatex Black "ultra" RTV

Make sure all wires, etc are pulled away from the intake area so no interference when putting intake manifold back on

rehearse putting intake back on without RTV so you can best determine how you hold it and how you lean over engine bay. you want to land the intake dead nuts without sliding it forward & back which can compromise RTV seal

Run a 1/4" bead of RTV on each china wall and run it up onto the intake gasket about 1/2" each side. Let RTV sit for about 15 min.

Some use short pieces of wood dowel (pencil) on one side front & rear bolt hole as guides to drop the intake back on

let car sit for 24 hrs after intake is back on before starting so RTV can cure

Not a full tutorial but a few steps I have used (although never did use studs as guide to drop intake on) and never had one leak after.
 
#29 ·
BallSS - thanks for the input and all you had listed there was on my agenda as I run through this process in my head. I'm off tomorrow and Friday so will see what pulling the intake reveals. Who knows, I may just get this all back together and discover nothing. If it does continue to leak, I will video what is going on and maybe someone will have some other suggestions. This leak based on what I've researched just seems to defy logic.

Oh...stopped at the one AZ store that had the Felpro MS95580 gasket set in stock, went out of my way to get it too. I even had him get his hands on it and hold it for me before I got there. The guy brings it out and it looked like some stomped on the damn box. I asked him to open the box to check the gaskets and they were mangled up pretty good. No way I'm going to use those and he understood why. All the other local AZ and Advances around me, of which there must be at least 5 of each store, did not have it in stock. At least the advance up the road from me will have it in tomorrow after 3.

I also had them order me in the EGR valve. I got the #EGR-1097 which they list for a 95 6speed camaro. This part is a BWD item and not AC Delco but I've had good luck with that brand.
 
Save
Reply Quote Like Like
#30 ·
Save
Reply Quote Like Like
#37 ·
100% I know it sounds crazy based on the design of this engine, but it was leaking out the 2nd Bolt back on the Driver side....read on :frown2:


BALLSS said:
using a washer on the small bolt to hold down the oil pump drive is not a bad idea

Do understand though that a old assembly top is more brittle and will crack if you put to much tq on the hold down bolt. I used a dab or blue loc-tite on the threads and a 1/4" drive to tighten.

IMHO if the cam is still stock there should be no reason to remove it
Click to expand...
Depending on what Metal I find at Home Depot, I may get a little creative. Thinking of tracing out the shape of the Plastic and at the round end extending out 2 Tangs. I'll then bend those over a Socket of the same dimension and it should help hold the sides together. If nothing available then a washer will work.


Ok Guys....Got the intake off and FOUND where it was leaking....but I'm CONCERNED! All the bolts for the intake came out pretty much Dry except for the 2nd Bolt back on the Drv Side. The first Pic shows the Bolts arranged from Front to Back and Driver Side on the Right. If you look closely you may see how the 2nd bolt is a little wet and the little puddle of coolant on the bench....hmmmm?

Based on what I've seen of these Heads and where that Bolt goes, it's into a open hole in the Engine Valley Area. How in the Heck is coolant coming out of there? Is it possible that the Hole is so close to a water Jacket and the Thread Sealer on that Bolt finally let go? Just so glad the coolant went up the Bolt and NOT down the bolt into the Engine Oil.....Phew! However, is my cylinder head Toast, will new thread Sealer on the Bolt "Plug it Up"....Gawd I sure hope so.

The 2nd Pic shows the bottom of the Intake Manifold at the Front Driver Side. If you look closely enough you can see the Droplets of Coolant in that where the Gasket was. Every other area of the intake surface was dry.

The 3rd pic is with the Gasket still on the Head. Again signs of coolant in that area but pretty much dry everywhere else on both heads. Also, you can see the Rust Outline on the head where it was burning off as it came out. Other head does not look like that.

4th pic is with the gasket removed and that 2nd hole back from the right is the Bolt Hole in question hear. This opening just goes right through into the Valley area. The Front bolt Hole to the right of it is just a Pocket that is not opened to anything.

I'll cross my fingers and hope that the Cylinder Head is not cracked and if it is (make prayers here Please 0:) ) that the Bolt Sealant will at least plug it up and I dont have to possibly swap a Head. Like I said, this seemed to defy logic but it sure appears from what I found that this is the culprit.

Be glad to hear your thoughts on this and is its possible for the Head to be cracked to allow this type of leak. Still feel fortunate that this did not wipe out the lower end of the engine.
 

Attachments

Save
Reply Quote Like Like
#33 · (Edited)
your purchase experience with the gasket kit I have had happen to me before.. example all stores DO NOT have the part but ONE store does have it .. that is the part is damaged returned and they try to sell to prevent loss to a sucker idiot.

advance auto store was looking for the warranty replacement for my opti ... one store had one .. it was all messed up then they could not get another so I got all my $$$ back..

I would get the gasket kit from rock auto much cheaper ..

http://www.rockauto.com/en/catalog/.../chevrolet,1996,impala,5.7l+v8,1049701,engine,intake+manifold+gasket+/+set,5424

$8 good deal ..

only 2 left I just ordered this kit includes even the injector O rings sweet deal ..
 
#35 ·
j cat said:
your purchase experience with the gasket kit I have had happen to me before.. example all stores DO NOT have the part but ONE store does have it .. that is the part is damaged returned and they try to sell to prevent loss to a sucker idiot.

advance auto store was looking for the warranty replacement for my opti ... one store had one .. it was all messed up then they could not get another so I got all my $$$ back..

I would get the gasket kit from rock auto much cheaper ..

1996 CHEVROLET IMPALA 5.7L V8 Intake Manifold Gasket / Set | RockAuto

$8 good deal ..

only 2 left I just ordered this kit includes even the injector O rings sweet deal ..
Click to expand...
This Gasket Set looked like it sat on their shelves for a while since it was a little Dusty and none of the other Stores even had it. Our parts are starting to not be stocked as much i guess.

Actually I think the Gasket Set took a wrong turn one night...down the wrong isle and ran into a Couple of Dead Batteries and a Monkey Wrench with a BAD Attitude. :smile2::laugh:
 
Save
Reply Quote Like Like
B
#34 ·
using a washer on the small bolt to hold down the oil pump drive is not a bad idea

Do understand though that a old assembly top is more brittle and will crack if you put to much tq on the hold down bolt. I used a dab or blue loc-tite on the threads and a 1/4" drive to tighten.

IMHO if the cam is still stock there should be no reason to remove it
 
B
#38 ·
Not seeing anything like a crack or how coolant could come "out" of the head onto intake bolt and go "up"....thinking the coolant is landing on the area of that bolt and migrating "down" onto bolt threads

obviously you have a closer view than we do. I see that intake bolt going through the head casting into the lifter valley. "maybe" the top threads of the hole do get close to the water jacket of the head and "maybe"...but man just not seeing that from my view (limited)

from this side of the keyboard I say you just use good thread sealer on the bolts and that should seal it

I know the source of coolant is still a mystery...
 
Chevy Impala SS Forum
posts
1.9M
members
48K
Since
2000
A forum community dedicated to Chevy Impala SS owners and enthusiasts. Come join the discussion about performance, modifications, troubleshooting, maintenance, and more!
Full Forum Listing
Explore Our Forums
Engine Problems/Maintenance Engine Performance Parts for sale/wanted Exterior Drivetrain